Synthesis of Long Afterglow Phosphors MAI204：Eu^2＋ , Dy^3＋ （M=Ca, Sr, Ba） by Microemulsion Method and Their Luminescent Properties

Long afterglow phosphors MAl2O4：Eu^2＋ , Dy^3＋ （M = Ca, Sr, Ba） were synthesized by microemulsion method, and their crystal structure and luminescent properties were compared and investigated. XRD patterns of samples indicate that phosphors CaAl2O4：Eu^2＋, Dy^3＋ and SrAl2O4 ： Eu^2＋, Dy^3＋ are with monoelinie crystal structure and phosphor BaAl2O4：Eu^2＋ , Dy^3＋ is with hexagonal crystal structure. The wide range of excitation spectrum of phosphors MAl2O4： Eu^2 ＋ , Dy^3＋ （M = Ca,Sr, Ba） indicates that the luminescent materials can he excited by light from ultraviolet ray to visible light and the maximum emission wavelength of phosphors MAl2O4：Eu^2＋ , Dy^3＋ （M = Ca, Sr, Ba） is found mainly at λem of 440 nm （M = Ca）, 520 nm （M = Sr） and 496 nm （M = Ba） respectively, the corresponding colors of emission light are blue, green and eyna-green respectively. The afterglow decay tendency of phosphors can he summarized as three processes： initial rapid decay, intermediate transitional decay and very long slow decay. Afterglow decay curves coincide with formula I = At^ - n, and the sequence of afterglow intensity and time is Sr 〉 Ca 〉 Ba.     

Synthesis of Long Afterglow Photoluminescent Materials Sr_2MgSi_2O_7∶Eu~(2 ), Dy~(3 ) by Sol-Gel Method

Withtheprogressofsocialcivilizationanddevel opmentofmodernscienceandtechnology ,thedemandforluminescentmaterialskeepsincreasingduetoitsgreatsocialandeconomicbenefits .Therefore ,prepa rationofluminescentmaterialswasregardedbypeopleveryearly .Asanembellish…     

Synthesis of Long Afterglow Phosphor CaAl_2Si_2O_8∶Eu~ (2 ), Dy~(3 ) via Sol-Gel Technique and Its Optical Properties

Inrecentyears,thelongafterglowphotolumines centmaterialhasbeenwidelyusedinmanyfields[1,2].Therareearthionsactivatedsilicatesbasedphosphor isbelievedasapromisinglongafterglowmaterialin thenearfutureforitshighchemicalandphysicalsta bility,especiallytheirwat…     

Synthesis and Luminescent Properties of Superfine Sr2CeO4 Phosphors by Sol-Gel Auto- Combustion Method

Citric acid complexing sol-gel auto-combustion method was explored to synthesize superfine Sr2CeO4 phosphors using the inorganic salts Sr（NO3）2 and Ce（NO3）3 as raw materials together with citric acid （CA） as a chelating agent. TGDTA, XRD, SEM and photoluminescence spectra were used to investigate the formation process, microstructure and luminescent properties of the synthesized Sr2CeO4. The results show that the crystallization of Sr2CeO4 begins at about 800 ℃ and completes around 900 ℃ with an orthorhombic structure. When the calcination temperature is above 1000 ℃, Sr2CeO4 partly decomposes into SrCeO3. SEM studies show that the particles of Sr2CeO4 obtained at 900 ℃ are sphericallike shape and superfine with diameter below 100 nm. The excitation spectrum of the superfine Sr2CeO4 phosphors displays a broad band with two peaks around 290 and 350 nm respectively. The former peak is stronger than the latter one. This broad band is due to the charge transfer （CT） band of the Ce^4＋ ion. Excited by a radiation of 290 nm, the superfine phosphors emit a strong blue-white fluorescence, and the emission spectrum shows a broad band with a peak around 470 nm, which can be assigned to the f→t1g transition of Ce^4＋ . It is found that the emission intensity is affected by the calcination temperature.     

SrAl_2O_4∶Eu~(2+),Nd~(3+) and Dy~(3+) Long Afterglow Phosphor

Longafterglowphosphorabsorbingenergyfromsolar,lampandotherlightsourcesforashorttimestorestheenergyandexhibitsbrightandlong lastingphosphorescencewhichsuitsthevisualperceptionofthehumaneyewithminimumbrightness 0 32mcd·m- 2 andlastingtimemorethan 8h) .TheSrAl2 O4 ∶Eu2 +,Dy3+phosphorhasbeenknowntobeagreenlongafterglowphosphorwithanemissionpeakat 5 2 0nm[1～ 7] .ThepropertiesofthephosphorwerefurtherexaminedbythegroupofTangMingdaoandMatsuzawaTindetailin 1995and 1996respectively[1,2 ] .Inorde…     

Synthesis and Luminescence Properties of Gd_2O_3∶Eu~(3+) Phosphors

Gd2 O3∶Eu3+ isanefficientredemittinglumines centmaterial ,whichcanbeappliedindisplays[1,2 ] .TheconventionalcommercialGd2 O3∶Eu3+ ismainlysynthesizedbyhightemperaturesolid statereactionandchemicalco precipitationmethods .Anadvancedperformanceofdisplaysrequireshighqualityphospho rssuchashighbrightnessandefficiency ,monodisper sityandfinegrainsize .Muchresearchhasanticipatedthatsubmicrometer sizedandnanometerluminescentmaterialswillhavethesepotentialadvantages[3～ 8] ,sosubmicrometer sizedan…     

Luminescent properties of MMgP_2O_7：Eu~（3＋）（M=Ca,Sr,Ba） phosphor

A series of red phosphors Eu3+-doped MMgP2O7(M=Ca,Sr,Ba) were synthesized by solid-state reaction method.X-ray powder diffraction(XRD) analysis confirmed the formation of pure CaMgP2O7,SrMgP2O7 and BaMgP2O7 phase.Photoluminescence spectra of MMgP2O7(M=Ca,Sr,Ba):Eu3+ phosphors showed a strong excitation peak at around 400 nm,which was coupled with the characteristic emission(350-400 nm) from UV light-emitting diode.The CaMgP2O7:Eu3+,SrMgP2O7:Eu3+ and BaMgP2O7:Eu3+ phosphors showed strong emission bands peaking at 612,593 and 587 nm,respectively.Due to the difference of the ion sizes between Ba2+(0.142 nm),Sr2+(0.126 nm),Ca2+(0.112 nm),Mg2+(0.072 nm) and Eu3+(0.107 nm),Eu3+ ions were expected to substitute for different sites in CaMgP2O7,SrMgP2O7 and BaMgP2O7 lattice.     

Luminescent Properties of BaMgAl_(10)O_(17)∶Eu~(2+) Phosphors Coated with Y_2SiO_5

BaMgAl_(10)O_(17)∶Eu~(2+)(BAM)is the blue compo-nent of the rare earth tricolor phosphor,and it hasbeen widely applied in tricolor fluorescent lamps duetoits highluminescent efficiency.However,deteriora-tion of this phosphor[1~5]li mits the lifeti me of thelamps.The deterioration of the brightness has twoforms:thermal deterioration and deterioration in igni-tion.Thermal deterioration mainly happens inthe pro-cess of lamp production.In general,it is consideredthat this deterioration comes f…     

Preparation and Luminescence Properties of the New Long Phosphorescent Phosphors Ba_(1-x)Ca_xAl_2O_4∶Eu ~(2 ), Dy~(3 )

Inrecentyears ,SrAl2 O4 ∶Eu2 ,Dy3 ,CaAl2 O4 ∶Eu2 ,Nd3 [1～ 8] andBaAl2 O4 ∶Eu2 ,Dy3 [9]havebeenconsideredasusefulblueandgreenphos phorsbytheirlongdurationphosphorescence .Howev er ,toourknowledge ,thephosphorBa1-xCaxAl2 O4 ∶Eu2 ,Dy3 hasnotbeeninvestigated .TheluminescenceofEu2 isverystronglydepen dentonthehostlattice ,whichcanoccurfromtheul traviolettotheredregionoftheelectromagneticspec trum .Itiswellknownthatthepersistentluminescenceisduetothetrappingofenergyinthed…     

(Sr1-xMx)Al2O4(M=Ca,Ba)∶Eu发光材料的研究

以SrAl2O4∶Eu发光材料为基础,通过对基质的部分修饰,合成了(Sr1-xMx)Al2O4(M=Ca,Ba)∶Eu磷光体,并利用XRD对其晶体结构进行了研究,结果表明:加入Ca后,原来在室温下稳定存在的属于单斜晶系的鳞石英结构SrAl2O4相逐渐变成六方晶系,证明Ca有稳定六方相的作用,而加入Ba晶形则不发生改变。同时研究了该发光粉的发射光谱,讨论了Ca和Ba的引入对发光性能的影响。     

Synthesis and Luminescence of SrZnO_2∶Eu~(3 ), Li~ Phosphor by Long Wavelength UV Excitation

Synthesis and Luminescence of SrZnO_2∶Eu~(3 ), Li~ Phosphor by Long Wavelength UV Excitation     

Synthesis of Phosphors(Ce_(0.67)Tb_(0.33))MgAl_(11)O_(19) and BaMgAl_(10)O_(17)∶Eu~(2 ) by Microwave Irradiation Technique and Their Luminescent Properties

Ｔｈｅｐｈｏｓｐｈｏｒｓ（Ｃｅ０．６７Ｔｂ０．３３）ＭｇＡｌ１１Ｏ１９（ＰＧ）ａｎｄＢａＭｇＡｌ１０Ｏ１７∶Ｅｕ２＋（ＰＢ）ａｒｅｗｉｄｅｌｙｕｓｅｄａｓｇｒｅｅｎａｎｄｂｌｕｅｌｕｍｉｎｅｓｃｅｎｔｍａｔｅｒｉａｌｓｉｎｒａｒｅｅａｒｔｈｓｔｒ...     

Synthesis of Long Afterglow Photoluminescent Materials Sr2MgSi2O7：Eu^2＋,Dy^3＋ by Sol-Gel Method

Long afterglow photoluminescent materials Sr2MgSi2O7 dopeo With Eu^2 ,Dy^3 were prepared by sol-gel method. The synthesized samples were characterized by X-ray diffraction. The excitation spectrum, emission spectrum and long decay curve were measured and analyzed. XRD pattern indicates that phosphor is with Sr2MgSi2O7 crystal structure. The wide range of excitation wavelength indicates that luminescent material can be excited by light from ultraviolet ray to visible light. The main peak of emission spectrum is located at 466nm. Sample excited by visible light can emit bright blue light, and the afterglow time lasts more than 8h.     

Synthesis of Y_2O_2S：Eu~（3＋） Phosphor by Microwave Thermal Effectand Its Luminescent Properties

ＳｙｎｔｈｅｓｉｓｏｆＹ_２Ｏ_２Ｓ：Ｅｕ~（３＋）ＰｈｏｓｐｈｏｒｂｙＭｉｃｒｏｗａｖｅＴｈｅｒｍａｌＥｆｆｅｃｔａｎｄＩｔｓＬｕｍｉｎｅｓｃｅｎｔＰｒｏｐｅｒｔｉｅｓＬｉＹｕａｎｙｉｎｇ（李沅英）；ＣａｉＳｈａｏｈｕａ（蔡少华）；ＤａｉＤｅｃｈａｎ?..     

Synthesis of CaO-SiO_2-B_2O_3∶Sm_2O_3 Glasses and Luminescent Properties of Sm~(3 )

Synthesis of CaO-SiO_2-B_2O_3∶Sm_2O_3 Glasses and Luminescent Properties of Sm~(3 )     

Synthesis and Electrical Properties of La0.6M0.4FeO3-δ （M = Ca, Sr, Ba） as Cathodes for SOFCs

Intermediate-temperature solid oxide fuel cells(IT-SOFCs) have attracted extensively attentionin re-cent years because of the potential to dramatically re-duce the cost of the materials and cell fabrication inaddition to i mprove reliability , portability and long-termperformance stability ,it has been regarded as ahigh green energyin 21st[1].However ,the experi men-tal results identifiedthat the ohmic losses of IT-SOFCslargely occurred from cathode polarization , and theknown cathode mate…     

Luminescence studies of MBrCl： Eu2＋ （M=Ca, Sr, Ba）

Europium doped MBrCl (M=Ca, Sr, and Ba) phosphors were prepared by solid state reaction in reductive atmosphere. Photolu-minescence (PL), photostimulated luminescence (PSL) after X-ray irradiation and optical absorption studies of MBrCl:Eu2+ (M=Ca, Sr, and Ba) revealed that: (1) blue light emission, under the excitation of 300 nm, was observed in all these phosphors; (2) the shape of the emission spectra in CaBrCl:Eu2+ could be changed by varying the bromine/chlorine ratio during synthesis, while that in SrBrCl:Eu2+ and BaBrCl:Eu2+ showed no change; and (3) PSL was observed in SrBrCl:Eu2+ and BaBrCI:Eu2+ after X-ray irradiation. Difference absorption spectrum (DAS) in SrBrCl:Eu2+ showed two broad bands centered at about 470 and 570 nm, and DAS in BaBrCI:Eu2+ showed two bands at about 550 and 675 nm, respectively. This enabled the use of He-Ne laser (633 nm) or even semiconductor light-emitting diodes (LED) instead of gas lasers for photostimulation.     

Luminescence Properties of Ce~(3 ) in KMF_3(M=Mg,Ca,Sr,Ba) Hosts with Perovskite Structure

ＬｕｍｉｎｅｓｃｅｎｃｅＰｒｏｐｅｒｔｉｅｓｏｆＣｅ３＋ｉｎＫＭＦ３（Ｍ＝Ｍｇ，Ｃａ，Ｓｒ，Ｂａ）ＨｏｓｔｓｗｉｔｈＰｅｒｏｖｓｋｉｔｅＳｔｒｕｃｔｕｒｅＺｈａｎｇＪｉｌｉｎ（张吉林）（ＬｉａｏｙａｎｇＰｅｔｒｏｃｈｅｍｉｃａｌＥｎｇｉｎｅｒｉｎｇ...     

溶胶—凝胶法制备长余辉发光材料SrAl_2O_4∶Eu~(2 ),Dy~(3 )的研究

用溶胶—凝胶法制备长余辉发光材料 Sr Al2 O4 ∶ Eu2 ,Dy3 ,选用柠檬酸合成前驱体柠檬酸盐 ,确定最佳烧结温度在 12 0 0～ 12 5 0℃范围 ,比一般高温固相法制备该产物降低了 2 0 0℃ ,其产物的发射光谱出现了明显“蓝移”现象。     

MTiO2（M=Mg,Ca,Sr,Ba）溶胶凝胶的合成和表征

在室温下用钛酸四丁酯的醇溶液和碱土金属硝酸盐Ｍ（ＮＯ３）２（Ｍ＝Ｍｇ，Ｃａ，Ｓｒ，Ｂａ）溶液的反应经过溶胶－凝胶法制备了多氧钛酸盐。在酸性条件下所获得的无定形凝胶在７００和９００℃温度之间煅烧制得了高纯ＭＴｉＯ２晶体粉末。用粉末Ｘ射线衍射（ＸＲＤ）、扫描电子显微镜（ＳＥＭ）和能量色散电子显微镜、热重（ＴＧ）、差热分析（ＤＴＡ）和ＢＥＴ表面积测量仪等研究了多种样品。Ｓｒ和Ｂａ的钛酸盐化合物稳定性好并